Originally Posted by 1slow370

yeah vtec is just a simple bitch version of VVEL in that it just increases the lift and duration of the camshaft above a certain rpm when an oil activated solenoid locks up the rockers/lifters in the valvetrain. our cars do it gradually vtec does it all at once hence vtec kicking in. in a race the revs would be up high enough that vtec would be kicked in all the time though so the whole kicking in thing in videos is just a way to hide the horrible power curve that only exists at the very top end or that the guy is using nitrous.

Interestingly enough though some of the vtec systems like that used on the D16z6 civic si engine (before the b16/b18) actually increased the lift on only one intake valve using the difference in pressure to generate swirl in the cylinder during the intake stroke. Also hondas next generation of vtec is going to be able to provide throttleable valve just like our vvel system does only it retains a camshaft so performance modifications could still be made and the head won't be deemed non servicable upon failure. VVEL is already becoming out dated, although i'm not sure if the honda system has released the redline for the new valvetrain although i fear it will still be able to reach 9000rpm.